Room unit for air conditioning



Jan. 23, 1962 c. ALLANDER ETAL 3, 1

ROOM UNIT FOR AIR CONDITIONING 2 Sheets-Sheet 1 Filed Jan. 20, 1960 vll7lllllllllllfi vllllfllll INVENTORSI CLAES ALLANDE R BIRGER L'A'RKFELDTWW ATTY8.

Jan. 23, 1962 c. ALLANDER ETAL 3,018,088

ROOM UNIT FOR AIR CONDITIONING Filed Jan. 20, 1960 2 Sheets-Sheet 2FIGS.

FIG4.

INVENTORSI CLAES ALLANDER BIRGER LARKFELDT' ATTYS.

United States Patent ()fiiice 3,018,988 Patented Jan. 23, 19623,018,t388 ROGM UNIT FOR AIR CONDITIONING Class Aliander, Soda-a Angby,and Birger Larkfeldt,

.lonkoping, Sweden, assignors to Aktiebolaget Svenska Fialtttabriken,Naclra, weden Filed .Ian. 20, 196i), er. No. 3,642 (Ilaims priority,application Sweden Jan. 26, 1959 6 Claims. (Cl. 257-137) The presentinvention relates to a room unit for air conditioning intended to besupplied with primary air, pre-treated in a central plant, which in theroom unit is mixed with ejected secondary air from the room. The unitconsists of a housing with a substantially rectangular cross sectionconnected to a duct for the supply of the primary air and having meansfor mixing with the primary air secondary air from the room by theejection effect. The unit includes heat-exchangers for conditioning thesecondary air connected to a pipe line for supplying either heating orcooling medium and is also provided with an inlet for said secondary airand an outlet for mixed primary and secondary air.

The invention relates to units of the above mentioned type which areprovided with a central shielded passage connected at its bottom to saidduct for the supply of the primary air or to a pressure chamber situatedin the lower part of the housing and connected to said duct. At the topthe passage is provided with nozzle means constituting the mentionedejection-mixing means. The heat exchanger is divided into two units,arranged on opposite sides of said central passage and the intake forthe secondary air consists of upper and lower inlet openings in thehousing located above and below the heat-exchangers respectively. Theupper openings are equipped with swingable dampers, arranged in one ofits end positions to close the passage of the secondary air through theheatexchangers and in its other end position to open said passage andinstead completely close the upper inlet passage.

Room units of the above mentioned type are nowadays be supplied witheither heating or cooling medium to make it possible to heat or cool theair according to the actual need with one and the same heat-exchanger.The size of the heat-exchange surface of the heat-exchanger isdetermined by the lower temperature difference used when cooling theair. This heat-exchange surface will, however, be unnecessarily largefor heating the air with accompanying difliculties for an adjustment asaccurate as desired for an individual final adjustment of the kind forwhich room units of the above mentioned construction are intended.

The new and improved room unit according to the invention ischaracterized in that the secondary air proportioning dampers arearranged to be adjusted simultaneously with and by the same mechanismwhich is used for operating the valve regulating the flow of the heatingor cooling medium in the heat-exchanger, and in such a way that duringadjustment of the valve from closed to open position first only one ofthe two secondary air proportioning dampers is turned from itsend-position closing the passage of the secondary air through theheat-exchanger to its other end position, while the turning of the otherdamper is started just after the first damper has reached its lastmentioned end position.

usually made in such a way that the heat-exchanger can Owing to the factthat the heat-exchanger in accordance with the invention is divided intotwo halves, arranged on both sides of the ejecting means and because ofsaid damper arrangement it is possible to put half of the heat-exchangerout of action when the heat-exchanger is supplied with heating medium.By shutting down half of the heat exchanger, an unnecessary over-heatingof the secondary air can be avoided. By an adjustment of the dampers tosuitable intermediate positions furthermore the proportion betweentreated and non-treated secondary air as well as the proportion betweenprimary air and secondary air can be varied, whereby the possibility toadjust the air temperature is further improved both when it comes toheating or cooling. The dampers can also be used for the adjustment ofthe air temperature even in those cases when the primary air is shut OEand the secondary air is caused to pass the heat exchanger halves onlyby self-draft.

The central passage may preferably be provided with a separatelyoperated shut-oft damper in order to make possible to shut oil thesupply of the primary air. To accomplish the simultaneous adjustment ofthe two secondary air proportioning dampers and the valve, the valveaccording to an appropriate embodiment is made with an extended spindle,arranged half-way between the pivotal axes of the dampers, and connectedto an adjustment knob on top of the room unit. For the adjustment of thetwo dampers, a cylindrical drum provided with two tracks is mounted onsaid spindle. The dampers are provided With crank levers mounted ontheir pivotal shafts, which directly or via a link-mechanism engage saidtracks. The tracks are designed so that the dampers are adjusted in theabove mentioned way. For strengthening of the ejecting eifect from theprimary air there is, according to an additional feature of theillustrated embodiment, a venturi channel between the heat-exchanger andthe outlet situated on top of the room unit, which channel at its lowerend communicates with the outlet side of the heat-exchangers as well aswith the mentioned upper inlets of the housing. In the same way theupper part of the central passage, between the heat-exchangers which isconnected with the ejecting means, can be made as a venturi passage.

The invention will now be closer described with reference to theaccompanying drawing showing an exemplifying embodiment of a unitaccording to the invention.

FIG. 1 shows a vertical cross section through the unit taken on the line1-1 of FIG. 3.

FIG. 2 also shows a vertical cross section through the unit taken on theline 2-2 of FIG. 3 close to the end of the unit.

FIG. 3 is a front elevation of the conditioning unit with the casingbroken away.

FIG. 4 is a section of the cam drum and housing taken on the line 44 ofFIG. 2.

FIG. 5 is a perspective view of the cam drum removed from the unit.

In the drawing, the illustrated embodiment of the room unit comprises ahousing 1 having a duct 2 for the supply of primary air and a nozzle 3connected to the duct by means of a central passage or pressure chamber8 for the primary air, which nozzle serves as a means for the ejectionand mixing of secondary air from the room. Two heat-exchanger halves orunits 4a and 4b are arranged on opposite sides of the central passage 8and are designed for either heating or cooling the secondary air fromthe room. The secondary air is taken into the unit either through twolower inlet openings 5a and 51) or through upper inlet openings 6a and6b. An outlet 7 on the top of the unit exhausts the mixed primary andsecondary air, which passes through a venturi channel 33 arrangedbetween the heat-exchanger units 4a and 4b and the outlet 7. Swingabledampers 9a and 9b are pivoted on shafts 10a and ltlb respectively. Eachdamper is arranged to shut oil? in one of its end positions A thepassage 41a or 41b for the secondary air through the associatedheated-exchanger half, and in its other end position B to completelyopen the passage 41a or 41b and instead of this, completely shut ofl thepassage 42a or 42b between the channel 33 and the upper inlets 6a and 6bfor the secondary air.

In accordance with the invention, a common means is provided foradjusting the dampers 9a and 9b, and a valve 12 which regulates theheating and cooling heatexchange medium in the heat-exchanger halves 4aand 4b. The valve 12 is connected at one side to an outer supply line 13and at the other side by means of a pipebend 14 to one of theheat-exchanger units 4b, which by means of a connection 14a (FIG. 3) isjoined to the other heat-exchanger unit 4a, the outlet of which isindicated at 15. The valve 12 has an extended spindle 16 which isdisposed half-way between the turning shafts Mia and 10b of theproportioning dampers. The spindle is connected to an adjusting knob 11.The spindle 16 and knob 11 serve as the common adjustment means becauseof an adjusting means 17 mounted on the spindle for adjusting thedampers 9a and 9b in accordance with the invention. The adjusting means17 consists of a cylindrical drum 18 enclosed in a casing 19. The drumis provided with two tracks 29 and 21 forming cam surfaces for twofollower rollers 22a and 22b which support two rods 23a and 23b, thelower ends of which form a yoke enclosing rolls 25a and 25brespectively. The rolls 25a and 2511 are mounted on the damper shafts10a and 1% by means of crank levers 26a and 26b. The rods 23a and 23bare biased downwardly by springs 24a and 24b to press the followerrollers 22a and 22b against their respective tracks. The tracks 20 and21 in the drum 18 are so constructed that during adjustment of the valve12 from closed to open position, at first only one of the dampers-An theillustrated embodiment 9b-is turned from its end position A for closingthe passage 41a to its other end position for closing the passage 42a.When the damper 9b reaches the limit position B the other damper, in theillustrated embodiment 9a, is actuated from its position A to itsposition B. In order to prevent direct communication between the upperand lower inlets for the secondary air, packings 1a and 1b are insertedbetween the housing 1 and the respective heat-exchanger units 4a and 4b.

Through an adjustment of the dampers to suitable intermediate positions,the proportion between treated and non-treated secondary air as well asthe proportion between primary air and secondary air can, as mentionedabove, be varied. The amount of primary air is intended to be keptconstant at a pre-set value. In order to facilitate the keeping of saidvalue constant there isin the illustrated apparatusa volume flowgovernor 27 mounted in the passage 8 immediately above the outletopening of the primary air duct 2. The value of the primary air volumecan be varied by changing the working position of the volume flowgovernor, which change is made by means of a mechanism 28. To completelyshut off the supply of primary air when necessary the unit is providedwith a damper 29 turnable around a shaft 30, and arranged in the passage8 just above said volume flow governor 27. The damper 29 is intended tobe operated Separately, i.e. independently of the above mentioneddampers 9a, 9b. In the illustrated apparatus the adjustment is made bymeans of a disc 31 attached to the shaft 30, an operating rod 32,attached to a bridge 33 and two adjustment knobs 34a, 34b. To obtain aninstantaneous adjustment between the end positions for the damper 29,the disc 31 is actuated by a spring 36, coiled around a pivoted rod 35which is tiltable between two over-center positions. To guaratee an evendistribution of the primary air through the ejecting nozzle withoutdisturbing sounds and with the least possible pressure drop, the upperpart of the central passage located between the heat-exchanger units andconnected to the ejecting means is made as a venturi channel 37. For thestrengthening of the ejecting eifect from the pnimary air, the channel38 is a venturi passage.

The unit housing shown in the drawing can without departing from theidea of the invention be omitted and replaced by furring built-in at theerection place, which furring possibly can be common for several roomunits. The embodiment of the adjusting means 17 shown in the drawing canwithout departing from the idea of the invention be varied by usingother guiding and transferring elements. In order to prevent both theheatexchanger halves from being opened when heating medium is suppliedto the heat-exchanger halves, ie to limit the operation of the damperadjustment mechanism in accordance with what is mentioned above, so thatonly one of the dampers is actuated, this mechanism may suitably beprovided with a stop element which limits the turning operation carriedout by means of the knob 11. This stop element can suitably be arrangedto be automatically actuated by a temperature sensitive instrumentmounted on the supply pipe line for the heating and cooling mediumrespectively. Said element can also be made to simultaneously carry outan automatic reverse of the indication symbols, intended to indicate theproper turning direction for the adjustment knob 11 for the respectivekind of medium to change the room climate towards warmer.

What we claim is:

I. In a room unit for air conditioning having a primary air inlet duct,a central passage connected at its lower end to said inlet duct andterminating at its upper end in an ejection nozzle, two heat-exchangerunits mounted on opposite sides of said central passage, secondary airinlets to introduce secondary air into the room unit for mixing withsaid primary air by ejection, said secondary air inlets including anupper opening operable to bypass the air in a passage around saidexchanger units to mix with said primary air at said ejection nozzle anda lower opening operable to direct the air in a passage through Saidheat-exchanger units to mix with said primary air at said ejectionnozzle, and a damper for each unit operable to proportion the flow ofsecondary air through said bypass and heat-exchanger passages, thedamper in its first limit position opening said bypass passage andclosing said heat-exchanger passage and in its second limit positionclosing said bypass passage and opening said heatexchanger passage, aconduit supplying heat-exchange medium to said heat-exchanger units anda valve regulating the flow of heat-exchange medium through said units,the improvement comprising a single operating mechanism for said dampersand said valve operable during operation of said valve from closed toopen position to first displace one of said dampers from its first toits second position while retaining the other damper in its firstposition and thereafter during said operation of said valve to displacethe other damper from its first to its second position while retainingsaid one damper in its second position.

2. A room unit according to claim 1 including a separately-operated shutofr damper in said central passage to shut off the flow of primary airtherethrough.

3. A room unit according to claim 1 wherein said single operatingmechanism includes a turning shaft for each damper, a spindle for saidregulating valve projecting upwardly between said shafts and terminatingin an adjusting knob, said spindle mounting adjusting means cooperablewith dampers to efiect said sequential displacement of said dampers.

4. A room unit according to claim 3 including operating lever means onsaid dampers to pivotally displace the latter on their turning shafts,said adjusting means comprising a generally cylindrical drum having twotracks forming cam surfaces engaging said lever means to effect saidsequential displacement of said dampers upon rotation of said spindle tooperate said valve.

5. A room unit according to claim 1 including a venturi flow passageconnected at its lower end to said heat exchanger passages, said by-passpassages and said ejection nozzle, and operable to exhaust air into theroom 15 2,567,758

References Cited in the file of this patent UNITED STATES PATENTS1,753,157 Otis Apr. 1, 1930 1,849,061 Anderson Mar, 15, 1932 2,144,466Stikeleather Jan. 17, 1939 2,238,689 Locke Apr. 15, 1941 2,287,267Palmer Iune 23, 1942 2,501,795 Stephens Mar. 28, 1950 Ashley Sept. 11,1951

